Cryptosteel Capsule Solo: Retired, and What Replaces It

The Cryptosteel Capsule Solo has been retired. Its page on the maker’s own store now redirects to the Seed24, and no Capsule appears in the shop at all, checked on 27 September 2026. Resellers still list it, sold out and silent about the replacement. An existing Capsule keeps working, because it has no firmware to abandon.

On this page: the maker’s own store checked on 27 September 2026, a table of what a 24 word phrase actually costs in characters computed from the BIP39 wordlist, and what a 20 ton press did to a capsule.

Almost every page ranking for this product name is a review with a commission attached, and not one of them mentions that the thing it recommends has been discontinued. So here is the state of it, verified today at source, plus the arithmetic on whether 123 characters is enough for a seed phrase.

Is the Cryptosteel Capsule Solo still on sale?

Not from the company that makes it. On 27 September 2026 the product URL for the Capsule Solo on cryptosteel.com resolves to the Seed24 product page instead of a Capsule page. The shop lists the Seed12 Security Kit, the Seed24 Security Kit, the Seed24 MAX Solo, Duo, Trio and Quintet, and the older Cassette Solo. There is no Capsule of any kind in it. The Cassette, the original 2013 era product, outlived the Capsule that replaced it, which is a pleasing result for anyone who distrusts moving parts.

Before that page came down it carried a clearance notice calling itself the final opportunity to buy the Capsule Solo, replaced by the next generation Seed24, and restricting sales to the US and EU. That wording is no longer reachable directly, so treat it as reported rather than quoted live. Resellers are a different story, and this is the part worth knowing before you click a review link. The Crypto Merchant still has a Capsule Solo product page at 99 dollars, reduced from 115, marked sold out, with nothing on it saying the line has ended. A search for the exact product name on Amazon.com the same day returned five results and not one was a Cryptosteel: two Keystone plates, an ELLIPAL plate, and two unbranded listings with the words crypto steel capsule wedged into their titles. That is the practical risk of shopping for a retired device. You do not find it. You find something arranged to look like it.

What is the Seed24, and what does it change?

The Seed system page calls the Seed range the new version of the Capsule, whose anatomy it says the Seed inherits. Same idea, then: stamped steel character tiles threaded onto a core inside a sealed shell. The vendor states the Seed24 stores a 24 word phrase, Shamir backups, multisig keys and strings up to 128 characters, and the Seed12 strings up to 64.

Three changes matter. The shell now has mounting holes at both ends for PSW-97 tamper evident seals, each with a serial number and a stated breaking strength of nearly 45 kg. The core is described as deformation resistant and locks with a double sided cotter pin. And the seals, tiles, separators and cotter pins are all stated to be compatible with the original Capsule, which is the single most useful sentence on the vendor’s site if you already own one.

Those prices were read during a September sale advertising up to 50 percent off, against list prices of 80 dollars for the Security Kit and 110 for the MAX Solo, which showed as out of stock. Opening the store from outside the US and EU showed every Seed24 variant as currently unavailable in your region, so the geographic restriction did not leave with the Capsule.

Does 123 characters really hold a 24 word seed phrase?

The number 123 is meaningless until you know what a seed phrase costs in characters, and that depends entirely on whether you write the words out.

BIP39 builds its wordlist so that the first four letters identify a word unambiguously. We downloaded the English wordlist and checked: all 2048 words are unique in their first four letters, with no exceptions. Word lengths run from three letters to eight, averaging 5.4. Cryptosteel relies on exactly this property and explains why, and its own instructions use a blank tile to fill the gap when a word is only three letters long, so an abbreviated word always occupies four slots.

Which gives the following, computed rather than quoted.

So the Capsule Solo clears a 24 word phrase with 27 characters spare and the Seed24 with 32. Neither holds one written out in full, because the average needs 130 and an unlucky phrase needs 192. That is the design rather than a defect: these devices are built around the four letter abbreviation, which is lossless because the wordlist guarantees it. The headroom is there for a passphrase or a SLIP39 share, not for spelling. A plate that stores numbers instead of letters has a different limit, which our Cryptotag Zeus review works through: a 20 word share fits its 24 slots, a 33 word share does not.

The number worth a second look is the Seed12 at 64 characters against an average full 12 word phrase of 65. Buy the small one intending to write your words out and roughly half of all 12 word phrases will not fit. Abbreviated, you need 48. Either way, our piece on the ways people actually lose a recovery phrase covers the transcription mistakes that have cost more coins than fire ever has.

What survived the stress tests, and what did not?

Jameson Lopp tested more than 70 metal seed products before ending the series, and the Capsule appears in Round III, published on 7 December 2019. His method: roughly 2000F for up to ten minutes, then submersion in water to imitate a fire crew, muriatic acid, and a 20 ton hydraulic press.

Heat and water: the Capsule came through readable, and Lopp reported no trouble reopening it by hand. Acid: none entered the capsule. The press is the finding that matters. Under 20 tons the tube bent, and because the end rod is permanently fixed, the cap could no longer be unscrewed. The tiles inside were undamaged and the words were intact. Getting at them would mean cutting the tube open around your own recovery phrase.

So the capsule is excellent against the failure people fear, fire, and has a specific weakness against one they rarely plan for: being crushed under a collapsed building or a heavy object. A flat stamped plate has no cap to jam. That is a real trade off, and no review with an affiliate link mentions it.

What do public accounts from buyers actually say?

Very little, and the silence is itself the finding. We read 34 posts across two bitcointalk threads, one of 20 posts from 1 to 3 December 2023 and one of 14 posts from 29 January to 3 February 2021, plus one published build log. For a product recommended this widely, almost nobody posting publicly had actually held one. Treat all of this as testimony, not evidence.

What recurs, from people considering it rather than owning it: fear of misspelling a word during assembly, fear of all the tiles sliding out at once, doubt about having enough letter tiles, and the price set against a hardware wallet. Several said they would rather have one punched plate than a bag of small parts. Others pushed back, noting that the separators stop words mixing and the end stop keeps the tiles in, which matches the vendor’s assembly instructions. One poster in February 2021, weeks after a large customer list leak, argued the real problem with any branded backup was the purchase record it creates.

The one first hand account we found is James Stanley, who published a build log on 20 January 2020 after deciding the Capsule at 89 euro was a bit expensive. He machined his own from stainless washers on a threaded rod for about 14 pounds in materials, and gave two reasons for preferring it: you do not lose the key even if you spill the washers, and the shorter body is easier to stash and less likely to bend if crushed. He reached the crush problem six weeks after Lopp demonstrated it.

Where these accounts agree with the official guidance: the steel does what the vendor says under heat and water. Where they do not: assembly is fiddlier than the marketing photographs suggest, and what people fear is human error with small parts rather than any property of the metal.

What does a metal backup not protect?

A metal backup defends the words against the weather and against time. That is the whole list. It does nothing about anyone who opens it, because your recovery phrase is sitting there in plain letters, as legible to a burglar or a builder or a relative as it is to you. There is no PIN, no attempt limit and nothing to brute force.

The documented answer to that is a BIP39 passphrase, sometimes called the 25th word, stored somewhere the capsule is not, which is one of the things the spare character capacity is for. SLIP39 splitting is the other, dividing the secret so that no single object found in a drawer is enough. Our piece on why the phrase is 24 words and what that cannot stop goes through what the length does and does not buy you.

The second thing steel cannot fix is the record of the purchase. In Ledger’s own disclosure of the July 2020 e-commerce breach, around one million email addresses were exposed, along with the name, postal address, phone number or order history of 9,500 customers. No wallet and no funds were touched, which was never the point: a list of verified addresses of people known to own bitcoin hardware is dangerous on its own. Cryptosteel now advertises unbranded discreet shipping and anonymous ordering, which suggests they understand the problem.

Never enter a recovery phrase into a website, an app or a support form that asks for it, whatever it promises to check. No legitimate tool needs it. If you have been leaving a phrase with a custodian instead, our page on which Coinbase product actually has a seed phrase explains what you are and are not holding.

What should you do if you already own a Capsule Solo?

Nothing urgent, and that is the honest answer. A discontinued phone stops getting security updates. A discontinued lump of stainless steel has no firmware, no companion app and no server to switch off, so end of life means only that you cannot buy another and cannot expect support. The vendor states that tiles, separators, cotter pins and seals carry over between the Capsule and the Seed range, so spares are still made.

What is worth doing is the thing most people never do: confirming the backup is readable and correct before they need it. Paper copies deserve the same treatment, and our page on where the leftover coins on a paper wallet actually go explains why an old sheet may hold less than you think. For where a backup belongs at all, start with what cold storage actually means.

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This article is educational and is not financial advice. Nothing here is a recommendation to buy, sell or hold anything. You are responsible for your own security decisions.